Skip to content

Commit 11c8721

Browse files
amitlanamitlan
committed
SQL/JSON: Fix some oversights in commit b6e1157
The decision in b6e1157 to ignore raw_expr when evaluating a JsonValueExpr was incorrect. While its value is not ultimately used (since formatted_expr's value is), failing to initialize it can lead to problems, for instance, when the expression tree in raw_expr contains Aggref nodes, which must be initialized to ensure the parent Agg node works correctly. Also, optimize eval_const_expressions_mutator()'s handling of JsonValueExpr a bit. Currently, when formatted_expr cannot be folded into a constant, we end up processing it twice -- once directly in eval_const_expressions_mutator() and again recursively via ece_generic_processing(). This recursive processing is required to handle raw_expr. To avoid the redundant processing of formatted_expr, we now process raw_expr directly in eval_const_expressions_mutator(). Finally, update the comment of JsonValueExpr to describe the roles of raw_expr and formatted_expr more clearly. Bug: #18657 Reported-by: Alexander Lakhin <exclusion@gmail.com> Diagnosed-by: Fabio R. Sluzala <fabio3rs@gmail.com> Diagnosed-by: Tender Wang <tndrwang@gmail.com> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/18657-1b90ccce2b16bdb8@postgresql.org Backpatch-through: 16
1 parent 52475b4 commit 11c8721

File tree

5 files changed

+92
-11
lines changed

5 files changed

+92
-11
lines changed

‎src/backend/executor/execExpr.c

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -2307,6 +2307,8 @@ ExecInitExprRec(Expr *node, ExprState *state,
23072307
{
23082308
JsonValueExpr *jve = (JsonValueExpr *) node;
23092309

2310+
Assert(jve->raw_expr != NULL);
2311+
ExecInitExprRec(jve->raw_expr, state, resv, resnull);
23102312
Assert(jve->formatted_expr != NULL);
23112313
ExecInitExprRec(jve->formatted_expr, state, resv, resnull);
23122314
break;

‎src/backend/optimizer/util/clauses.c

Lines changed: 18 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -2915,13 +2915,25 @@ eval_const_expressions_mutator(Node *node,
29152915
case T_JsonValueExpr:
29162916
{
29172917
JsonValueExpr *jve = (JsonValueExpr *) node;
2918-
Node *formatted;
2918+
Node *raw_expr = (Node *) jve->raw_expr;
2919+
Node *formatted_expr = (Node *) jve->formatted_expr;
29192920

2920-
formatted = eval_const_expressions_mutator((Node *) jve->formatted_expr,
2921-
context);
2922-
if (formatted && IsA(formatted, Const))
2923-
return formatted;
2924-
break;
2921+
/*
2922+
* If we can fold formatted_expr to a constant, we can elide
2923+
* the JsonValueExpr altogether. Otherwise we must process
2924+
* raw_expr too. But JsonFormat is a flat node and requires
2925+
* no simplification, only copying.
2926+
*/
2927+
formatted_expr = eval_const_expressions_mutator(formatted_expr,
2928+
context);
2929+
if (formatted_expr && IsA(formatted_expr, Const))
2930+
return formatted_expr;
2931+
2932+
raw_expr = eval_const_expressions_mutator(raw_expr, context);
2933+
2934+
return (Node *) makeJsonValueExpr((Expr *) raw_expr,
2935+
(Expr *) formatted_expr,
2936+
copyObject(jve->format));
29252937
}
29262938

29272939
case T_SubPlan:

‎src/include/nodes/primnodes.h

Lines changed: 9 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -1669,15 +1669,19 @@ typedef struct JsonReturning
16691669
* JsonValueExpr -
16701670
* representation of JSON value expression (expr [FORMAT JsonFormat])
16711671
*
1672-
* The actual value is obtained by evaluating formatted_expr. raw_expr is
1673-
* only there for displaying the original user-written expression and is not
1674-
* evaluated by ExecInterpExpr() and eval_const_expressions_mutator().
1672+
* raw_expr is the user-specified value, while formatted_expr is the value
1673+
* obtained by coercing raw_expr to the type required by either the FORMAT
1674+
* clause or an enclosing node's RETURNING clause.
1675+
*
1676+
* When deparsing a JsonValueExpr, get_rule_expr() prints raw_expr. However,
1677+
* during the evaluation of a JsonValueExpr, the value of formatted_expr
1678+
* takes precedence over that of raw_expr.
16751679
*/
16761680
typedef struct JsonValueExpr
16771681
{
16781682
NodeTag type;
1679-
Expr *raw_expr; /* raw expression */
1680-
Expr *formatted_expr; /* formatted expression */
1683+
Expr *raw_expr; /* user-specified expression */
1684+
Expr *formatted_expr; /* coerced formatted expression */
16811685
JsonFormat *format; /* FORMAT clause, if specified */
16821686
} JsonValueExpr;
16831687

‎src/test/regress/expected/sqljson.out

Lines changed: 49 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1300,3 +1300,52 @@ SELECT JSON_SERIALIZE('123' RETURNING sqljson_char2);
13001300
ERROR: value too long for type character(2)
13011301
SELECT JSON_SERIALIZE('12' RETURNING sqljson_char2);
13021302
ERROR: value for domain sqljson_char2 violates check constraint "sqljson_char2_check"
1303+
-- Bug #18657: JsonValueExpr.raw_expr was not initialized in ExecInitExprRec()
1304+
-- causing the Aggrefs contained in it to also not be initialized, which led
1305+
-- to a crash in ExecBuildAggTrans() as mentioned in the bug report:
1306+
-- https://postgr.es/m/18657-1b90ccce2b16bdb8@postgresql.org
1307+
CREATE FUNCTION volatile_one() RETURNS int AS $$ BEGIN RETURN 1; END; $$ LANGUAGE plpgsql VOLATILE;
1308+
CREATE FUNCTION stable_one() RETURNS int AS $$ BEGIN RETURN 1; END; $$ LANGUAGE plpgsql STABLE;
1309+
EXPLAIN (VERBOSE, COSTS OFF) SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': volatile_one() RETURNING text) FORMAT JSON);
1310+
QUERY PLAN
1311+
-------------------------------------------------------------------------------------------------------------
1312+
Aggregate
1313+
Output: JSON_OBJECT('a' : JSON_OBJECTAGG('b' : volatile_one() RETURNING text) FORMAT JSON RETURNING json)
1314+
-> Result
1315+
(3 rows)
1316+
1317+
SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': volatile_one() RETURNING text) FORMAT JSON);
1318+
json_object
1319+
---------------------
1320+
{"a" : { "b" : 1 }}
1321+
(1 row)
1322+
1323+
EXPLAIN (VERBOSE, COSTS OFF) SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': stable_one() RETURNING text) FORMAT JSON);
1324+
QUERY PLAN
1325+
-----------------------------------------------------------------------------------------------------------
1326+
Aggregate
1327+
Output: JSON_OBJECT('a' : JSON_OBJECTAGG('b' : stable_one() RETURNING text) FORMAT JSON RETURNING json)
1328+
-> Result
1329+
(3 rows)
1330+
1331+
SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': stable_one() RETURNING text) FORMAT JSON);
1332+
json_object
1333+
---------------------
1334+
{"a" : { "b" : 1 }}
1335+
(1 row)
1336+
1337+
EXPLAIN (VERBOSE, COSTS OFF) SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': 1 RETURNING text) FORMAT JSON);
1338+
QUERY PLAN
1339+
------------------------------------------------------------------------------------------------
1340+
Aggregate
1341+
Output: JSON_OBJECT('a' : JSON_OBJECTAGG('b' : 1 RETURNING text) FORMAT JSON RETURNING json)
1342+
-> Result
1343+
(3 rows)
1344+
1345+
SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': 1 RETURNING text) FORMAT JSON);
1346+
json_object
1347+
---------------------
1348+
{"a" : { "b" : 1 }}
1349+
(1 row)
1350+
1351+
DROP FUNCTION volatile_one, stable_one;

‎src/test/regress/sql/sqljson.sql

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -480,3 +480,17 @@ SELECT JSON_OBJECTAGG(i: ('111' || i)::bytea FORMAT JSON WITH UNIQUE RETURNING v
480480
CREATE DOMAIN sqljson_char2 AS char(2) CHECK (VALUE NOT IN ('12'));
481481
SELECT JSON_SERIALIZE('123' RETURNING sqljson_char2);
482482
SELECT JSON_SERIALIZE('12' RETURNING sqljson_char2);
483+
484+
-- Bug #18657: JsonValueExpr.raw_expr was not initialized in ExecInitExprRec()
485+
-- causing the Aggrefs contained in it to also not be initialized, which led
486+
-- to a crash in ExecBuildAggTrans() as mentioned in the bug report:
487+
-- https://postgr.es/m/18657-1b90ccce2b16bdb8@postgresql.org
488+
CREATE FUNCTION volatile_one() RETURNS int AS $$ BEGIN RETURN 1; END; $$ LANGUAGE plpgsql VOLATILE;
489+
CREATE FUNCTION stable_one() RETURNS int AS $$ BEGIN RETURN 1; END; $$ LANGUAGE plpgsql STABLE;
490+
EXPLAIN (VERBOSE, COSTS OFF) SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': volatile_one() RETURNING text) FORMAT JSON);
491+
SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': volatile_one() RETURNING text) FORMAT JSON);
492+
EXPLAIN (VERBOSE, COSTS OFF) SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': stable_one() RETURNING text) FORMAT JSON);
493+
SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': stable_one() RETURNING text) FORMAT JSON);
494+
EXPLAIN (VERBOSE, COSTS OFF) SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': 1 RETURNING text) FORMAT JSON);
495+
SELECT JSON_OBJECT('a': JSON_OBJECTAGG('b': 1 RETURNING text) FORMAT JSON);
496+
DROP FUNCTION volatile_one, stable_one;

0 commit comments

Comments
 (0)
pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.


Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy